Abstract

1. Syrian golden hamsters were treated with a single subcutaneous dose of 200mg of diethylnitrosamine/kg. In the liver the treatment produced a significant and early inhibition of the incorporation of orotic acid into RNA and of leucine into protein. Diethylnitrosamine also lowered basal and 20-methylcholanthrene-stimulated activities of hepatic aryl hydrocarbon hydroxylase. 2. RNA synthesis, protein synthesis and aryl hydrocarbon hydroxylase activity were also evaluated in the lungs of the same animals. In this organ only protein synthesis was affected by diethylnitrosamine, but not RNA synthesis or aryl hydrocarbon hydroxylase activity. 3. The incorporation of thymidine into DNA was inhibited in both organs early after diethylnitrosamine treatment and increased 2–3 days later. 4. Although diethylnitrosamine, injected subcutaneously, accumulates in liver and lung in toxicologically active amounts, the acute biochemical responses of the two organs are not identical.